Borja

Borja's roots go back to a Celtiberian settlement called Bursau, which minted its own coins and occupied the area around the Cueva Esquilar before spreading up the nearby hill of La Corona. Both Livy and Pliny the Elder recorded it, the former placing it among the Ebro valley towns during the Sertorian wars, the latter listing it as part of the legal district of Caesaraugusta. After the Roman conquest, settlements moved to the slopes of the hill, and later the population retreated back to La Corona as conditions became more dangerous.

The Muslim period brought the town its greatest growth; incoming rulers negotiated with the local Visigothic count, a man named Casio, and the town appears to have been known as Burŷa, from the Arabic word for tower or fortification. From this arrangement the Banu Qasi dynasty emerged, playing a significant role in the Muslim history of the Iberian Peninsula. The Christian reconquest was peaceful: Muslims kept their properties and their faith, though they were required to move outside the walls to the area around Calle San Juan.

A longstanding local claim holds that the Borgia family — before their name was Italianised — originated here, but the connection remains unproven.

The collegiate church mixes styles across its history: a mudejar exterior, a single-nave baroque interior, and a cloister added in an earlier century, with a portico attached later. Inside, the main altarpiece, the organ, and a set of Gothic panels in the sacristy stand out. One of the towers still bears the visible scar of a cannonball from the 1706 siege during the War of Spanish Succession.

The castle and town walls have their origins in the Islamic period, when Borja's position above the Huecha valley made it strategically important. What survives today is fragmentary — much of the stone was quarried over the centuries for use in other buildings.

Borja still has around a hundred rock-cut cave wine cellars, part of a tradition of some four hundred across the wider Campo de Borja region. Cut into the hills of La Corona, Cueva Esquilar, and south of the castle hill, they typically consist of a vaulted main chamber reached by a short passage, with side niches for barrels and a ventilation shaft to release fermentation gases. The earliest recorded request to dig one dates to 1863.

The town hall, built in 1534 by local master builder Antón de Veoxa, is a notable example of Aragonese brick architecture. Its ground floor entrance has carved stone lintels; the main floor features wrought-iron balconies and a Hall of Kings displaying portraits of Aragonese monarchs who granted privileges to the town, painted in a later century.

The church of San Miguel, Gothic-mudejar with a Romanesque apse, now houses the city's Archaeological Museum, run in collaboration between the town council and the Centro de Estudios Borjano.